;/*
; * FreeRTOS Kernel <DEVELOPMENT BRANCH>
; * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
; *
; * SPDX-License-Identifier: MIT
; *
; * Permission is hereby granted, free of charge, to any person obtaining a copy of
; * this software and associated documentation files (the "Software"), to deal in
; * the Software without restriction, including without limitation the rights to
; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
; * the Software, and to permit persons to whom the Software is furnished to do so,
; * subject to the following conditions:
; *
; * The above copyright notice and this permission notice shall be included in all
; * copies or substantial portions of the Software.
; *
; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
; * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
; * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
; * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
; *
; * https://www.FreeRTOS.org
; * https://github.com/FreeRTOS
; *
; */

#include "FreeRTOSConfig.h"

; Variables used by scheduler
;------------------------------------------------------------------------------
    EXTERN    pxCurrentTCB
    EXTERN    usCriticalNesting

;------------------------------------------------------------------------------
;   portSAVE_CONTEXT MACRO
;   Saves the context of the general purpose registers, CS and ES (only in far
;   memory mode) registers the usCriticalNesting Value and the Stack Pointer
;   of the active Task onto the task stack
;------------------------------------------------------------------------------
portSAVE_CONTEXT MACRO

    PUSH      AX                    ; Save AX Register to stack.
    PUSH      HL
    MOV       A, CS                 ; Save CS register.
    XCH       A, X
    MOV       A, ES                 ; Save ES register.
    PUSH      AX
    PUSH      DE                    ; Save the remaining general purpose registers.
    PUSH      BC
    MOVW      AX, usCriticalNesting ; Save the usCriticalNesting value.
    PUSH      AX
    MOVW      AX, pxCurrentTCB      ; Save the Stack pointer.
    MOVW      HL, AX
    MOVW      AX, SP
    MOVW      [HL], AX
    ENDM
;------------------------------------------------------------------------------

;------------------------------------------------------------------------------
;   portRESTORE_CONTEXT MACRO
;   Restores the task Stack Pointer then use this to restore usCriticalNesting,
;   general purpose registers and the CS and ES (only in far memory mode)
;   of the selected task from the task stack
;------------------------------------------------------------------------------
portRESTORE_CONTEXT MACRO
    MOVW      AX, pxCurrentTCB      ; Restore the Stack pointer.
    MOVW      HL, AX
    MOVW      AX, [HL]
    MOVW      SP, AX
    POP       AX                    ; Restore usCriticalNesting value.
    MOVW      usCriticalNesting, AX
    POP       BC                    ; Restore the necessary general purpose registers.
    POP       DE
    POP       AX                    ; Restore the ES register.
    MOV       ES, A
    XCH       A, X                  ; Restore the CS register.
    MOV       CS, A
    POP       HL                    ; Restore general purpose register HL.
    POP       AX                    ; Restore AX.
    ENDM
;------------------------------------------------------------------------------
